Hadith 2:235

Narrated Qatada:

Anas bin Malik said, "The Prophet (p.b.u.h) and Zaid bin Thabit took
their Suhur together. When they finished it, the Prophet stood for the
(Fajr) prayer and offered it." We asked Anas, "What was the interval
between their finishing the Suhur and the starting of the morning
prayer?" Anas replied, "It was equal to the time taken by a person in
reciting fifty verses of the Quran."